Turner



June 4, 1929. s. TURNER INCANDESCENT LAMP Filed Feb. 18, 1928 igg :a |171--- Huw.. ...Uilm

Patented .lune 4,v L1929.,

unire; stares rilassa rarest erstes.

sTEsLinG TURNER, or SALEM, MASSACHUSETTS, Assrenoie To, HYGRADEALAMP co., or SALEM, MASSACHUSETTS, `A, CORPORATION or MASSACHUSETTS..

INCANDESCENT LAMP.

rlhis invention relates to incandescent elec'- tric lamps and more especially to gas filled lamps of this character.

In using incandescent lamps lilled with nitrogen, argon, or other gas, especially where suoli lamps are connected in series as, for example, on street railway circuits, it is a common'experien'ce for an arc lto form in a lamp due to the breaking of a ilament. Such an arc may create suflicient heat to cause the lampto explode, or the arcV may follow up the leading-in wires, burn out the base, and even burn into the socket and fixture in which the lamp is supported.V It has been proposed heretofore to prevent destructive arcing of this character by enclosing theleading-iu wires in glass tubes, the tubes being so supported that they will be released automatically upon the formation of an arc and will then drop and tend to cut off the are. It vhas been found, however, that such an arrangement cannot be depended,r upon. ln some `cases a tube will be released by the are in the manner contemplated and the arc then will flash across to the part of the leading-in wire abovethe tube- In other cases the tube will stick andthe arc will cut its way through a tube, following upthe leading-in wire with the same ultimate result as though the tube were not present. While it has been proposed to prevent the latter occurrence by using tubes vof fusedquartz, this'involves a relatively large increase in the expense of manufacture of the lamp.

The present invention deals with the problem presented by these conditions, and it aims to devise' a lamp construction in which an karc createdin the manner above described will be automatically extinguished, and to accomplish Vthis result with va construction inv which the manufacturing expense will be held. within reasonable limits.

The nature of the invention will be readily understood from' the following descriptionv when read 1n connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

ln the drawings,

Figure 1 is a perspective view of a lamp constructed in accordancewith this invention, certain of the parts being shown broken alla?? Fig. 2 1s a view similar to Fig. 'out showlng" pesitmn the 'when eine of the insulating tubes has been released by the formation of an arc; and

Fig. 3 is a cross-sectional view, partly in elevation, showing certain details of construction on a larger scale.

rlhe lamp structure shown comprises a glass envelope or bulb 2 equipped with the usual base 3 and stem 4. The glass bulb preferably is filled with a gas such as argon, nitrogen,-

or the like. Projecting downward from the press portion of the stem is a pedestal 5 havmg a series of wires sealed into the lower extremity thereof for supporting or steadying the filament 6. Current-is conducted to the lilament by leading-in wires 7 7', respectively. The arrangement so far described is substantially like that of lamps of well known constructions.

According to the present invention the leading-inwires 7 7 are enclosed in and protected by insulating tubes 8-8,` respectively, these tubes extending from the press of the stem' 4 down nearly to the end of each leading-in wire. The .tubes kare held permanently on'v the leading-in wires in any suitable manner, as'for example, by bending the leading-in wires at intermediate portions, as clearly shown in the drawings, so thatfeach tube will be held frictionally on its respective wire. Slidably mounted Von the tubes 8 8 are insulating sleeves 9-9, respectively. ln order to hold the sleeve`9 in its elevated position, as shown in Fig. l, a small wire l() is sealed in the lower end of the-pedestal 5, while its other end is wrapped around the lower portion of the leading-in wire 7, the lower edge of the tube 9 resting on this wire, as clearly shown in Fig. l'. A similar construction is used to support the other tube 9', and the parts used for this purpose are shown on a larger scale in` Fig. 3. Tliesewvires lO-10 may be made' of'any material which will support the sleeves in their elevated positions duringshipment and normal operation of the lamp, but which will'melt out vreadily and release the tubes upon the forniathe lea'dingiinwires it quickly iusesfone or both of the meltable wires l--l0, thusreleasing at least one of the sleeves 9 or 9. The sleeve sovreleasedimmediately drops until its lower end strikes-the inner surface of -tlie Vglobe 2,*and it therefore cuts off and extinguishes the are. The sleeves 9-v-9 sli'de freely on the tubes 8--8, respectively, and anyfpossibility of the sticking of the sleeves is avoided,

' and the manufacturing expense'is within .en-y

ti rely satisfactory limits.

Atthe -sametime-the sleevefand tube for eacli leading-in wireaielmade of such length-that Vwhen ythe sleeve has dropped, las :shown for examplein l? ig. 2, the entire (length et' the leading-in wire isenclosed in theinsulating member-s and thereis no opportunity for the c arc tostrike back to anenposedgportion of the wire. Y ,Y Y. 1 Y

The tubes, 8-8l and the sleeves,9-9 may ,be made "of any suitable insulating material.

-I liaveobtained fvery satisfactory `results by making they tubes 8 8 of common glassiand -tlie sleeves 9-v9rof'a more refractory or higher melting lpoint glass, such for example, as Vthatdinowncommercially as Pyrex glass. 'It is contemplated,liowever, that `these parts, and partieularlyltlie sleeves, may b'e made of other insulating material, such iiorexample, as mica, or a material know-naskisolantite.

The construction above described has proved in `practice `to be extremely reliable lVhile I have herein-sli'ownand describedapreferred :en'ibodiment of my invention, vit

=will be understoodfthattlie invention may be embodied .in other -torins withoutdeparting from the spirit or scope thereof.

vIdesireto claim asfnew is: y

l. In Aan incandescent electric-lamp, the

combination olailament, leading-in wires ii'or saidiilament, a protector Vtorrone of said V4wires, andan insulating vsleeve' sli'dable on s'aidjproteetor. Y

2. In an incandescent elect-ric lamp, Vthe Y `sltlaving thus describedmy invention, what combination'o'f a filament, leading-in L,wires for saidiilament-,a :protector ,for one oit said VWires, anl insulating sleeve slidable on -said ,piotector, and Ymeans 'for holding saidlsleeve fnormally in an inaetiveposition but adapted Vto V.release vthe sleeve upon the V`formation of an tarc between said :wires 3; In anki'neandescent .electric lamp, the combination of ya -filament,leadingin wires l.orsaid iilament,'an-insulating tube renclosing eneof saidwires, andan insulating sleeve loosely :encircling said tube and'y lslidably y' mounted thereon, said tube and sleeve serving toprotect said ,-vvire and toextinguisli an arc between said wire. Y f

r4 ln `an Vincandescent electric lamp, the

conibinationof a iil'ament, leading-in wires .orf'said filament'yan insulating tube through which one oi' said wires extends for a con- VVsiderable distance, said tube iit'ting closely around-said 'wi-re, an 4ins'iilatii'i'g sleeve lloosely encircling said tubeand slidable thereon, and means for holding said sleeve normally in an Yinactive position but adapted to release the sleeve automatically upon the formation of 'an are between said wires. a a

k5. In an. incandescent electricilanip, the

combination ot a lfilament leading-in wires for said lilainent, a pedestal for supporting ,said filament, an insulating sleeve through which said AWire extends for a considerable distance, said sleeve beingslidable relatively to said wire, and means connected with said pedestal for releasably holding said sleeve :normally in aniiiactive position, said means being adapted to releasesaid sleeve upon the formation oi'an arc between said wires.

G. rln an incandescent electric lamp, the

rcombinationof a filani'ennvleading-in wires 'for said yiilanient, a pedestal for supporting said filament, an insulating sleeve through which said wire extends for a `considerable f distance, said sleeve being slidable relatively Vto said wire, and means connecting the wire v`so enclosed with said .pedestal for releasably holding saidsleeve normally in inactive positiomsaid means being adapted to release said sleeve uponr the formation of an arc between said wires. 4

7. In an incandescent,electric lamp, the combination oft' a iilament, leading-in wires for said iilanient, a pedestal for supporting said filament, aninsulatingtiibe enclosing one of said'wires and permanently held thereon, a

sleeve of refractory insulating :material rencircling said tube and'slidable thereon, and a meltable wire connecting said pedestal with the leading-inwire enclosed in said tube and lsupporting said sleeve in position to be remel'table Wire holding saidsleeve in an elevatedfposition but adapted to Arelease the sleeve uponthe 'formation of an are between said wires to permit said sleeve to drop and cut ofli tlieaic, said sleeve and tube being of such l'engtlisas to protect the entire length of ,the leading-in wire when the sleeve has droppedto the lower Y limit of its movement.

sTniiLi'Ne TURNER. 

